With over 12,500 dengue cases in Delhi, a green NGO today claimed that the ongoing fogging drive in the city was "not effective" in fighting the vector-borne disease, and has rather "harmful" effects on health, as the gas contains "95 per cent" of diesel in it.
Saying that fogging only creates a "false" sense of security and is a way of "appeasing" people at the cost of their health, Centre for Science and Environment (CSE) urged the government to focus on systematic preventive measures towards clean environment and sanitation.
Its assessment said that 4.5 lakh litre of diesel could be used this year for fogging, which comes to 4,500 litres of diesel per day and is also equivalent to the usage of diesel by 2,000 cars in a day.
Quoting medical experts, CSE said that the direct inhalation of diesel fumes, combined with insecticides, can exacerbate asthma or bronchitis among those with respiratory ailments while pregnant women, small children and old people are most susceptible to aggravation.
"We looked into the issue when community members approached us and shared their observations and experiences. We found that fogging is ineffective in containing dengue and has a harmful effect on the health of people," CSE Deputy Director General, Chandra Bhushan said.
Till October 17, at least 12,531 reported cases and 32 deaths have officially been recorded in Delhi, the highest number of cases since 1996.
The rise in cases from 778 in August to 6,775 in September and 4,925 by mid-October alone indicates the negligible effect of fogging, CSE claimed.
It said that fogging knocks down only the adult mosquito and not the larvae that are the source of breeding. Larvicide measures, on the other hand, are recognised as an important intervention to prevent large-scale spread of dengue.
Elaborating further, CSE said that fogging mix usually contains around "95 per cent" of diesel along with an insecticide mostly malathion while at times, petrol is also added.
"This means a vehicle-mounted container typically has 95 liters of diesel which is used up in one round of fogging. Several rounds by the vehicle in a day could mean several hundred litres of diesel per vehicle," it said.
"Fogging only creates a false sense of security among people and diverts attention from preventive action for dengue by the state and community. It is only a way of appeasing people at the cost of their health.
"The government needs a systematic sanitation drive and emphasis on clean surroundings so that mosquito does not get breeding grounds. The community has a very important role in play in controlling dengue by keeping private premises clean," Mr Bhushan said.
CSE said that targeting adult mosquitoes offers temporary control and that too in limited settings and under ideal conditions and unless repeated frequently, fogging cannot control the next batch of adults out of the larvae.
"This is why, source control through larvicide measures is considered effective, said Amit Khurana, head of Food Safety and Toxins Programme at CSE.
The municipal corporations of South and East Delhi have already spent about "Rs 70 lakh" on diesel for fogging till October 10 this year, the CSE further claimed.
Considering the total area of Delhi, the remaining days of the fogging season and the price of diesel, the estimated total diesel use could go "over 4.5 lakh litres this year".
"Keeping a 100-day fogging-intensive season, this is about 4,500 litres of diesel per day, which is equivalent to diesel used by over 2,000 cars in a day," CSE said.
It said that the WHO guidelines on dengue too "questions" the role of fogging and recognises that fogging has been used by South-East Asian countries for the past 25 years but has not been effective.
Diesel is known to contain carcinogens and malathion, a class III pesticide is also known as slightly hazardous by the WHO. Once sprayed, this "concoction" is not only inhaled but is also absorbed in soil and water, it noted.
"Medical experts suggest that direct inhalation of diesel fumes, combined with insecticides, can exacerbate asthma or bronchitis among those with respiratory ailments.
"Pregnant women, small children and old people are most susceptible to aggravation. Eye specialists also mention that diesel fumes can also cause irritation and itching on skin and eyes. Prolonged exposure could lead to temporary swelling of the corneas," CSE said.
It said that the focus of the government should be on long-term preventive measures and creating awareness among people.